Unable to set default program

[antares]

Hi, I'm trying to associate the .epub extension with an installed program (an ebook reader, Icecream). I do this in multiple ways: right clicking on the file and choosing "Open with"/Use this app for all epub files" and then choosing the program from the list, and by going to Control Panel/Default Programs/Set Associations but after I associate .epub with Icecream it still shows "Current Default Not Selected". Any idea how to fix this? Thanks